Fig. 5

Age-related increases in hippocampal IL-6 are more pronounced in cytosolic versus nuclear or membrane fractions. To determine if age-related increases in IL-6 were more likely to impact the membrane-associated classical anti-inflammatory pathway or the soluble trans-signaling pro-inflammatory pathway, hippocampi from C57BL/6J mice were subjected to biochemical fractionation to separate proteins into nuclear (N, nuc), cytosolic (C, cyto), and membrane (M, memb) fractions. A Validation of biochemically fractionated samples suggests minimal contamination of the nuclear fraction with unsheared cells as we find histone 3 in the nuclear fraction but not cytosol or membrane, pAKT enriched in the cytosol fraction, and synaptophysin in the membrane but not nuclear or cytosolic fraction. B In the ventral hippocampus (VHIPP), old mice showed higher expression of IL-6 relative to young mice in the nuclear, cytosolic, and membrane fractions. C The dorsal hippocampus (DHIPP) showed the same pattern with old mice expressing higher levels of IL-6 relative to young mice in the nuclear, cytosolic, and membrane fractions. Across the ventral and dorsal hippocampus, the age-related increases that were observed in the cytosolic fractions were approximately twice those observed in the nuclear and membrane fractions. Data expressed as mean ±SEM. Brightness and contrast of blots adjusted for graphical clarity. Post hoc: #vs nuclear and membrane, P<0.001; *vs young, P<0.002